Thanks Greentree. The answer is that irrespective of being part-time or full-time, once you have two years service you are entitled to statutory redundancy (at a min). An employer cannot use part-time employment as a mechanism to avoid this.
If redundancy is to be offered, It has to be averaged out over the full length of your service, and given that you were full time for most of this you will get a payment based upon this.
In terms of how long this can go on, this is really something you need to discuss with your employer based upon the need to go three days in the first place. Obviously the firm is suffering in the current climate; however is this expected to continue or is there light at the end of the tunnel?